The BIOS revisions listed below have been found to cause an error with Bit Locker where it will not enable/resume when TPM is in TPM 2.0 mode.If you have recently updated your system BIOS to the version below please update again to the new version shown from the Dell Support Site to resolve the issue.I believe some of you already gone through this but this small workaround is for the people who is looking for a quick relief.When a computer BIOS is updated or the switches changed in the BIOS config; the Bit Locker would realize that the signature has been changed and it would not boot.
That way, you won't have to enter the recovery key at all. This scenario describes how to either suspend Bit Locker Drive Encryption or turn off Bit Locker Drive Encryption and decrypt the drive.When you have encrypted an operating system drive, you can choose to either suspend Bit Locker temporarily or turn off Bit Locker on an operating system drive and decrypt the drive.A: If anything changes around the boot configuration of your machine, Bit Locker prompts for the recovery key before you can continue using the machine.(By the way, many actions can cause changes to the boot configuration, including BIOS updates; find a full list of causes at the Microsoft article "Bit Locker Drive Encryption in Windows 7: Frequently Asked Questions.") To fix this, after you boot into Windows, you must suspend, then resume, Bit Locker.